Many readers shared their thoughts on the three themes of 2008: the Economics of Energy, Design for Good and Climate Change. Here are some of the year's best emails.
Put your questions to our Principal Voices using the form below. Remember to tell us who your question is for.
It's simple to comment on a story. Just click the "sound off" box at the bottom of the page.
Send your thoughts to CNN's newest online forum iReport.com. It's the best way to share your photos and videos.
These days it seems everyone's a member of an online community. Join ours! You can find us on facebook here